She's 5" high, just under 13cm, not counting her hairbow or the stand. Penny for scale.

Changes to make:
Make blouse plain white, the fine lines don't show up well anyway, and it seems to have caused some black spots.
Make mouth line thicker, it breaks up at this scale.
Might thicken her eye outline since part wasn't printed, though that looks like a one-time print error.
Better finger placement on cane, some fingers came out looking too thin.
Already done: made stand a bit smaller, made skirt a brighter green, added pattern to shoes.

The lighting makes the figure look more sparkly than it is in real life. I think it looks really, really, good.

Once I get all the girls set up and print a set that looks good, I'll post the datafiles. I'm planning on a .x3d file for each girl plus texture files for faces, etc. Let me know if there are other formats people want for 3D printers -- my files will be .zip files that will work as-is for shapeways (Lilly is printed in color sandstone). 3D printing services charge by cubic centimeter of material; Lilly, being the tallest with her cane, long hair, and hairbow, is also the most expensive; since she lacks arms, Rin is nearly half Lilly's price.

Printing them smaller & cheaper is possible, but there's more of a chance of bits breaking off. Lilly seems complete, but I get warnings for parts like her hair, and I had to thicken her cane quite a bit, so shrink at your own risk. My models all start out the same size (makes bodies, clothes, etc, easier to make for everyone), but my tests will have them scaled to proper relative sizes.

I accidentally made school Hanako a bit too small - she's only about 90% of what her size ought to be. The rest are in correct proportions.

Model errors

The ends of Misha's drills didn't come out attached, and Lilly and Shizune lost some fingers in the hot springs poses (Shizune's index finger on her glasses also gets thinned out too much).

I should be able to make Misha's hair more solid and put everyone's fingers closer together so their hands don't render as individual fingers but are solid, like mittens.

The next defect seems to be due to variations in printing -- my first Lilly model has much better definition for the bottom edge of her blouse, with the small "notch" in front and two points in back. The new printing has everyone's blouse smooth in front and not as well defined in back. Since my new tests have pretty much the same blouse as the old tests, I don't know if I can improve this. It's possible the blouse quality was better when it had an (almost entirely white) texture file instead of being a solid color -- I'll go back and try using the blouse textures again.

The last rendering problem is squarish-looking arms and legs (their arms have 8 sides and their legs 12 sides), due to using models geared more towards video games, where a lower polygon count is preferred for speed and using smooth shading to hide it. 3D printers use the actual polygons. In the photos, it's easier to see on their school uniforms, but in real life it's more noticable when they're nude since they're a single color. But from a few inches away it can't be seen. It would be more work to fix than it's really worth, unfortunately.

Color errors

Rin's hair came out nearly black instead of dark red. Hanako's scars are almost invisible and look more like bruises. Skirt colors are still the same dark green (maybe I forgot to change it?) Lilly's hair is too orange -- the first try was a lot better. Hanako's hair is probably darker than people would like. Everyone's nipples are very hard to see, and their skin tones seems a bit too saturated.